JPH09327161A - Structure for salient-pole synchronous generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a salient-pole synchronous generator whose efficiency is high and which is low-cost by a method wherein the coil end of an armature is arranged in a direction which is separated from an axial line within a specific range with reference to the rotor shaft of the generator and the coil end is made shorter. SOLUTION: An armature winding 2 is housed in a slot 1a which is formed at the inner face of a stator core 1. A rotor 5 is arranged so as to be rotatable at the inside of an armature by keeping a gap with reference to the inner face of the stator core 1. In the armature winding 2 which is housed in the slot 1a at the stator core 1, parts 2a which protrude to the outside at both ends in the axial direction of the stator core 1 at intervals of slots are connected electrically to each other, and they are bent so as to cross. The parts 2a are called coil ends, they are bent outwards within a range of θ2 =30 to 50 deg., and the length of every coil end 2a is made shorter than that in conventional cases. Thereby, the resistance of the armature winding 2 can be reduced, and the coil ends 2a can cross and spatially arranged easily.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has a power generation output of several hundred KW.
The present invention relates to a generator structure for improving the efficiency of a small-to-medium-sized salient pole type synchronous generator.

[0002]

2. Description of the Related Art Conventionally, a four-pole salient-pole synchronous generator, which is low in cost and easy to manufacture, has been widely used for a generator having a power generation output of several hundred KW, which is driven by a gas engine, for example. In general, generator losses include other losses including iron loss, rotor loss, armature copper loss, mechanical loss, and stray load loss, but when it comes to this class of generators, all of these losses are combined. The loss is about 7 to 8%, and the efficiency as a generator is generally about 92 to 93%.

[0003]

Conventionally, in order to improve the efficiency of this class of salient-pole synchronous generator, the following measures have been considered. (1) Reduction of iron loss Iron loss is reduced by using a high-grade silicon steel plate for the laminated core of the armature (stator). Generally, in combination with measures for reducing armature copper loss and rotor copper loss, which will be described later, the iron core frame is often enlarged to improve efficiency. (2) Reduction of rotor copper loss The rotor copper loss (I ² R _r ) is reduced by increasing the size of the excitation coil wire of the rotor (rotor) to lower the electrical resistance R _r . In this method, since the diameter of the rotor increases, the diameter of the armature also needs to increase, which causes a problem of cost increase. (3) Reduction of armature copper loss Increase the armature winding strand size to reduce the electrical resistance R _s ,
Reduce armature copper loss (I ² R _s ). For this purpose, it is necessary to increase the throttle for accommodating the armature winding, which increases the diameter of the armature, resulting in an increase in cost.
However, reducing the armature copper loss, which accounts for about 30% of the total loss, is of great significance in improving the efficiency of the generator, so it should be adopted together with the measures in (1) and (2) above. There are many. Specifically, the diameter of the armature is increased, a high-grade silicon steel plate is used for the laminated iron core, and the magnetic flux density of the throttle tooth portion is changed from 1.2 to 1.3 T (Tesla) to 1.4 to 1.
This is a method of increasing the number of turns of the armature winding by raising it to 5T (Tesla). This method reduces the armature copper loss and iron loss by 3
Although it can be reduced by about 0 to 50%, there is a problem that the cost is increased by about 30%. (4) Reduction of mechanical loss In addition to the inherent wind loss due to the rotation of the rotor and sliding friction loss of the bearing, mechanical loss is directly connected to the rotor shaft for cooling the armature and rotor winding. Although there is wind loss due to the cooling fan that has been taken into consideration, the mechanical loss is reduced to 30% by reducing the fan capacity in combination with the iron loss reduction effect of the above (1) measure and the copper loss reduction effect of the above (3) measure. The degree can be reduced. However, it was considered impossible to further reduce the mechanical loss due to the uneven rotor structure unique to the salient pole machine.

In view of the limits of the conventional efficiency improving measures as described above, the present invention reduces various losses and improves cooling performance by a relatively simple structural device without increasing cost and weight. An object is to provide a salient-pole synchronous generator with high efficiency and low cost.

[0005]

In order to achieve the above-mentioned object, the present invention is, in the first embodiment, in a range of 30 ° to 50 ° with respect to the rotor axis of the generator with the coil end of the armature. The coil end is arranged in a direction away from the axis and is shorter than the coil end of the conventional output machine.

In the second embodiment of the present invention, the stainless tape is spirally wound around the peripheral surface of the rotor.

In the third embodiment of the present invention, the outer periphery of the coil end portion of the rotor is wrapped with a heat resistant fiber cloth, the periphery of the fiber cloth is fastened with a thin heat resistant rope, and then treated with an insulating varnish.

In a fourth aspect of the present invention, a slot wedge formed by coating a grooved thin steel plate with an insulating resin tape and processing it so as to have an open U-shaped cross section is used as a slot wedge of an armature. Used as.

According to the fifth aspect of the present invention, a small fan for sucking cooling air and a small fan for discharging cooling air are arranged at both ends in the axial direction of the generator, and the sucked air and the discharged air are discharged. A rectifying plate was installed to regulate the flow.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is an axial sectional view of a salient pole type synchronous generator according to the present invention in which an armature is provided with measures for improving efficiency.

Reference numeral 1 denotes a cylindrical stator iron core formed by stacking die-cut silicon steel plates. An armature winding 2 is formed in an axially extending slot 1a formed on the inner surface of the stator iron core 1. Are stacked and stored. This is the armature of a synchronous generator. Inside the armature, a rotor 5 is rotatably arranged with a gap of 2 to 3 mm from the inner surface of the stator core 1.

The armature windings 2 housed in the slots 1a of the stator core 1 intersect with each other at intervals of several slots, the portions 2a of the stator core 1 which are located outside the axial ends of the stator core 1 being electrically connected to each other. Is bent like. This portion 2a is called a coil end and is a portion that does not induce a voltage,
In the conventional salient pole type synchronous generator, the coil end 2a is within a range of θ ₁ = about 10 ° to 20 ° with respect to a line parallel to the rotor axis of the generator as shown by a chain line in FIG. Bent outward (away from the central axis of the generator). On the other hand, in the present embodiment, the coil end 2a is bent outward in the range of θ ₂ = 30 ° to 50 °, and the length B ₂ of the coil end 2a is about 180 mm, which is the conventional coil end length. It is about 20% shorter than B ₁ (about 220 mm). By doing so, the resistance of the armature winding 2 can be reduced, and the coil ends 2a can be easily crossed and arranged in space.

However, when the coil end 2a is bent in this way, the coil end 2a comes close to the stator core 1 and there is a risk of corona discharge occurring between the two. Therefore, in this embodiment, the coil end 2a is The outer side (on the side of the stator core 1) is wrapped with a glass fiber tape and an insulating varnish is applied from above. By performing such a treatment, the corona prevention treatment 3 is performed between the coil end 2a and the stator core 1.

As confirmed by the present inventors, the bending angle of the coil end 2a is made larger than in the conventional case as in the present embodiment, and the corona prevention treatment 3 is applied to the armature winding 2
It was possible to reduce the resistance value of No. 10 by about 10% and also reduce the armature copper loss by 10%. Moreover, the insulation performance of the coil end 2a was certainly enhanced.

FIG. 2 is a perspective view of the rotor of the salient pole type synchronous generator according to the present invention in which the rotor is provided with measures for improving efficiency.

The illustrated rotor is composed of a rotor core 6 formed by stacking die-cut silicon steel plates, has four magnetic poles, and a rotor winding 7 for excitation is wound between the poles. The rotor winding 7 is held by a coil bracket 8 and fixed by a coil fixing bolt 8a. A stainless tape 9 having a thickness of about 0.05 mm and a width of about 20 mm is provided on the peripheral surface of the rotor 5 with a tape interval of 0.
The tape 9 and the rotor core 6 are spot-welded (indicated by a black circle 10 in the figure) between the tapes while being wound in a spiral shape with a gap of about 5 to 1 mm. This is to prevent the tape 9 from being separated from the rotor core 6 by centrifugal force during the rotation of the rotor. The position of this spot welding is set to a position close to the center of each of the four magnetic poles, as can be seen from FIG. 2C, so that the insulation of the rotor winding 7 is not adversely affected by the heat during welding. Is good. The length of the tape at the welded portion in the lengthwise direction is 2 to 3 mm. TIG welding may be used instead of spot welding.

By winding the stainless tape 9 around the peripheral surface of the rotor 5 in this way, the unevenness of the surface of the rotor magnetic pole becomes close to a perfect circle, and the windshield loss and mechanical loss can be reduced to almost zero. As an additional effect, unnecessary eddy current loss due to the stainless tape does not occur.

FIG. 3 shows the end portion of the rotor of the salient pole type synchronous generator according to the present invention in which the rotor is also provided with efficiency improvement measures. FIG. 3A is an end view of the rotor, and FIG. 3B is a side view of the end.

Similarly to the armature shown in FIG. 1, the end of the rotor winding 7, that is, the coil end, has a complicated concavo-convex structure at the end of the rotor 5 in the axial direction. Is a considerably large value (a generator with an output of 300 KW can reach about 1 KW). Therefore, in this embodiment, as shown in FIG.
As shown in (a) and (b), a polyimide amide cloth 13 of heat-resistant and strong fiber is wound around the outer circumference of the coil end portion 12 of the rotor 5, and the outer side thereof is further covered with a thin rope 14 of polyimide amide. Tighten tightly with. After that, varnish treatment is performed to form a deformed dodecagonal shaped solid tubular band ring. In the figure, 8 is a coil end bracket and 8a is a coil fixing bolt, both of which are shown in FIG.
It is the same as that shown in (a).

By winding the cloth 13 on the outer circumference of the coil end portion 12 of the rotor winding 7 in this way, the uneven structure of that portion can be made close to a circular shape, thereby making windbreak wind loss close to zero. be able to. As a result, the insulation of the coil end portion 12 is strengthened, which makes it possible to extend the service life and extend the maintenance cycle. By the way, in the past, the coil end was heavily soiled, and it was necessary to disassemble and inspect it every few years, but this is no longer necessary.

FIG. 4 shows an example of an armature slot of a salient pole type synchronous generator according to the present invention in which the armature is provided with a measure for improving efficiency.

As shown in (a), an electric machine made of glass-coated rectangular copper wire, which is mainly insulated with, for example, mica tape, in a slot 1a having a width of 10 to 15 mm and a depth of 40 to 60 mm formed in the stator core 1. The sub winding 2 is housed in two layers, upper and lower. Armature winding 2 housed in slot 1a
On the upper surface of the upper layer and the bottom surface of the lower layer, a slot liner 20, which is a cushioning material for glass tape, is provided.

A slot wedge 21 as shown in FIG. 4B is fitted into the entrance of the slot 1a. As shown in FIG. 4 (c), the slot wedge 21 of the present embodiment is a thin steel plate 2 having a thickness of about 0.5 mm, which is formed by fine grooving on both front and back surfaces at intervals of 0.5 to 1 mm like a stapler.
1a is coated with a polyester tape 21b, and then the whole is pressed into a U-shape with an open cross section (trapezoid without bottom). By forming the grooves on the front and back surfaces of the silicon steel plate 21a with a fine feeling, the electrical resistance in the longitudinal direction of the slot wedge 21 can be increased, so that the eddy current generated by the rotating magnetic field can be suppressed to a small value, and the heat generation can be suppressed. It is effective in reducing the problem.

Although the conventional slot wedge is a glass-based polyester resin laminated plate having a trapezoidal cross section and a thickness of about 5 mm, the slot wedge 21 of this embodiment has an open U-shape (a base without a base). Because of the shape, the effective area in the slot can be increased by about 5%, and the cross-sectional area of the armature winding accommodated in the slot in the same slot as the conventional one can be increased by 5%. Therefore, the armature copper loss can be reduced by 5%.

Further, since the slot wedge of this embodiment is a magnetic wedge made of a grooved thin steel plate, it has an effect of reducing the magnetic resistance of the slot tooth portion, and if the magnetic flux densities are the same, the magnetomotive force of the rotor is reduced. It can be reduced by 2 to 3% and rotor copper loss can be reduced by about 5%.

Further, the entire armature winding is varnished (vacuum impregnated) at the time of manufacturing, but at that time, the varnish also enters the polyester tape 21b of the slot wedge 21, so that the insulation performance is automatically enhanced.

FIG. 5 is a schematic side view of a salient pole type synchronous generator whose efficiency is improved by improving the cooling fan.

In the conventional generator of this type, one large fan having a large diameter (capacity of required power of 3 to 7 KW) is installed on one side of the generator to cool all heat generated by the rotor and the armature. There are many examples. In the present invention, by taking the measures of the first to fourth embodiments, the capacity of the cooling fan can be reduced. For example, if you needed a fan with 3KW capacity,
2KW fans will be enough. Therefore, in the present embodiment, as shown in FIG. 5, the diameter is smaller than that of a conventional cooling fan on both sides of the generator, that is, on the cooling air intake side (the right side of the generator in the figure) and on the discharge side (the left side of the generator in the figure). Small cooling fan 25, 26 of 0.8 kW, for example
And one air conditioning plate 27a, 27b and 28a, 28b for optimizing the flow of the cooling air, respectively. The flow of cooling air by the cooling fans 25 and 26 is indicated by arrows in the figure.

Even if the capacities of the cooling fans 25, 26 are reduced in this way, the mechanical loss can be reduced without lowering the cooling capacity in combination with the functions of the air flow regulating plates 27a 27b, 28a, 28b, and the internal parts of the generator can be reduced. Can improve the cooling performance.

The inventors of the present invention have adopted a standard 300 KW salient-pole synchronous generator and a high-efficiency generator 3 which has taken the conventional efficiency improvement measures.
All of the efficiency improvement measures proposed in the present invention were applied to each of the 00 KW salient-pole synchronous generators, and each loss, efficiency, cost, and weight were compared with the conventional one. Table 1 shows the results.

[0032]

[Table 1] As can be seen from Table 1, the loss can be reduced for all loss items in both the standard type and the high-efficiency type, and the reduction of mechanical loss is particularly remarkable. As a result, it was possible to improve the efficiency by 1.5% or more in the standard type and 1.0% in the high efficiency type. On the other hand, there was almost no increase in cost and weight required for improving efficiency in both the standard type and the high efficiency type. The effects not shown in the table are improvement of the insulation performance of the rotor and improvement of the mechanical strength of the rotor and armature coil end portions.

In the present invention, it is not necessary to apply all of the above-mentioned five types of efficiency improvement measures to the generator, and it is possible to apply a combination of some measures while checking the balance between cost and efficiency.

[0034]

As described above, by applying the efficiency improving measure according to the present invention to any or all of the armature, the rotor, and the cooling fan of the salient pole type synchronous generator, the cost and weight are increased substantially. 1-2% efficiency without
Can be raised. In addition to that, improvement of the insulation performance of the rotor and improvement of the mechanical strength of the coil end portions of the rotor and the armature can be expected.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a salient pole type synchronous generator according to the present invention in which an armature is provided with a measure for improving efficiency.

FIG. 2 shows a rotor of a salient-pole type synchronous generator according to the present invention in which efficiency improvement measures are taken, (a) is a perspective view of the rotor,
(B) shows a state in which stainless steel tape is wound around the surface of the rotor, and (c) is an axial end view of the rotor.

3A and 3B show a rotor of a salient-pole synchronous generator according to the present invention in which another measure for improving efficiency is taken, where FIG. 3A is an axial end view of the rotor, and FIG. 3B is a coil end portion of the rotor. FIG.

FIG. 4 shows a slot wedge of an armature of a salient pole type synchronous generator according to the present invention in which efficiency improvement measures are taken, (a) shows a state in which an armature winding is housed in the slot of the armature, (b) )
Shows a perspective view of the slot wedge, and (c) shows a manufacturing process of the slot wedge.

FIG. 5 is a schematic diagram of a salient-pole synchronous generator according to the present invention in which a cooling fan is used to improve efficiency.

[Explanation of symbols]

 1 Stator Iron Core 1a Slot 2 Armature Winding 2a Coil End 5 Rotor 6 Rotor Iron Core 7 Rotor Winding 9 Stainless Steel Tape 12 Coil End 13 Polyimideamide Cloth 21 Slot Wedge 21a Grooved Thin Steel Plate 21b Polyester Tape 25, 26 Cooling fan 27a, 27b, 28a, 28b Air conditioning plate

Claims (8)

[Claims] 1. A coil end of an armature is arranged in a direction away from an axis of a generator rotor within a range of 30 ° to 50 ° and is shorter than a coil end of a conventional output machine. A salient-pole synchronous generator characterized in that 2. The salient pole type synchronous generator according to claim 1, wherein corona prevention treatment is applied between the coil end of the armature and the armature core. 3. A salient pole type synchronous generator characterized in that a stainless tape is wound in a spiral shape on a peripheral surface of a rotor. 4. The salient-pole synchronous power generation according to claim 3, wherein the stainless tape is wound around the rotor circumferential surface with a slight gap, and the stainless tape and the rotor core are welded at the gap. Machine. 5. A salient-pole synchronous power generation characterized in that the outer periphery of the coil end portion of the rotor is wrapped with a heat-resistant fiber cloth, the periphery of the fiber cloth is fastened with a thin heat-resistant rope, and treated with an insulating varnish. Machine. 6. A projection characterized in that a slotted thin steel plate is covered with an insulating resin tape, and a slot wedge processed to have an open U-shaped cross section is used as a slot wedge of an armature. Polar synchronous generator. 7. A small fan for intake of cooling air and a small fan for exhaust of cooling air are respectively arranged at both ends in the axial direction of the generator, and air regulating plates for restricting the flow of the intake air and the exhaust air are provided. A salient-pole synchronous generator characterized in that 8. The coil end of the armature is arranged in a direction away from the axis of the generator in the range of 30 ° to 50 ° with respect to the rotor axis, and is shorter than the coil end of the conventional output machine. Corona prevention treatment is applied between the coil end and the armature core, and a stainless tape is wound spirally on the peripheral surface of the rotor, and the outer circumference of the coil end portion of the rotor is wound with a heat-resistant fiber cloth. After tightening around the circumference with a thin heat-resistant rope, it was treated with an insulating varnish, and a thin steel plate grooved as an armature slot wedge was covered with an insulating resin tape to form an open U-shaped cross section. Using machined slot wedges, a small fan for intake of cooling air and a small fan for exhaust of cooling air are installed at both ends in the axial direction of the generator, and air conditioners that regulate the flow of cooling air are installed. A salient pole type synchronous generator characterized by the fact that